It is well known to use cycle reversing valves to control the operation of heat pumps. These valves, often referred to as "four way valves" or "switch over valves", are used to reverse the refrigerant line connections to a compressor, such that the heat pump can either pump heat into or out from a building (e.g., a house).
Cycle reversing valves for use in heat pumps typically are provided with a flow plate through which there are port passages. Flow is controlled by a "bathtub" which moves to cover and uncover ports in the flow plate. The bathtub shape requires an abrupt 180 degree turn of the suction flow. However, the "bathtub" causes a loss of efficiency or SEER loss. This loss occurs through the suction gas line and the discharge gas line of the heat pump and from heat transfer. In particular, suction gas loss results from the restriction in the flow plate and the 180.degree. bend of the bath tub. The discharge gas loss results from abrupt changes in expansion and contraction, as well as from the flow path of the discharge line. Cold suction gas inside the "bathtub", which is surrounded by hot discharge gas, causes heat transfer loss.
Numerous patents are directed to reversing valves which attempt to improve the efficiency of the heat pump and/or simplify its operation by modifying the structure and configuration of the valve member. These valves include ones providing control for the opening or shutting the discharge and suction ports through direction of pressure differential between the high and low side of the system. Other valves use complex switching and control elements, which may include numerous springs, cylinders and pistons, in an attempt to improve the efficiency of the heat pump. Still other valve designs attempted to modify the valve member itself, for example, by providing a butterfly valve, to increase efficiency and simplify construction. Still other valve structures included multiple chambers or multiple valves in an attempt to simplify the design or increase efficiency of the reversing valve.
Overall, the known reversing valves do not sufficiently reduce or limit the losses that occur in heat pumps. Therefore, what was needed was a new reversing valve to reduce or limit efficiency loss, while providing a less complex design for controlling and/or shifting the reversing valve, which had fewer component parts.